1. Technical Field
The invention relates generally to automotive weatherstrips, and more particularly to such a weatherstrip whose hardness can be varied in response to operative door conditions.
2. Description of the Prior Art
In the design and manufacture of automobiles, the provision of weatherstrip seal members in the gap between vehicle doors and the adjacent body structure has presented challenging problems. There is a need for sophisticated compromise between providing an effective fluid-tight seal in the gap to isolate the vehicle passenger compartment from the elements and minimizing the effort required to close the door to its latched or locked position. The primary fluid-tight sealing requirement, which is of most importance when the vehicle is in operation and the door is closed, is generally best achieved through providing a relatively hard weatherstrip. On the other hand, a relatively soft weatherstrip can best accommodate the requirement to minimize closing efforts of the door. Accordingly, the hardness of a weatherstrip that is chosen for use in an automotive vehicle is a compromise between the ideal hardness to reach the two opposing goals.
Because of this need to compromise, it is recognized by those skilled in the art that it would be desirable to provide a weatherstrip having a hardness that would vary in response to the operating conditions of the door in the vehicle.